package com.hmdp.service.impl;

import cn.hutool.core.bean.BeanUtil;
import cn.hutool.core.collection.CollectionUtil;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.hmdp.dto.Result;
import com.hmdp.dto.UserDTO;
import com.hmdp.entity.Follow;
import com.hmdp.entity.User;
import com.hmdp.mapper.FollowMapper;
import com.hmdp.service.IFollowService;
import com.baomidou.mybatisplus.extension.service.impl.ServiceImpl;
import com.hmdp.service.IUserService;
import com.hmdp.utils.UserHolder;
import org.springframework.data.redis.core.StringRedisTemplate;
import org.springframework.stereotype.Service;

import javax.annotation.Resource;
import java.util.Collections;
import java.util.List;
import java.util.Set;
import java.util.stream.Collectors;

/**
 * <p>
 * 服务实现类
 * </p>
 *
 * @author 虎哥
 * @since 2021-12-22
 */
@Service
public class FollowServiceImpl extends ServiceImpl<FollowMapper, Follow> implements IFollowService {

    @Resource
    private StringRedisTemplate stringRedisTemplate;

    @Resource
    private IUserService userService;

    @Override
    public Result follow(Long followUserId, Boolean isFollow) {
        // isFollow true关注 false 取关
        Long userId = UserHolder.getUser().getId();
        String userFollowKey = "follows:" + userId;
        if (isFollow) {
            // 关注
            Follow follow = new Follow();
            follow.setUserId(userId);
            follow.setFollowUserId(followUserId);
            boolean save = save(follow);
            if (save) {
                stringRedisTemplate.opsForSet().add(userFollowKey, followUserId.toString());
            }
        } else {
            // 取关
            boolean remove = remove(new QueryWrapper<Follow>()
                    .eq("user_id", userId)
                    .eq("follow_user_id", followUserId)
            );
            if (remove) {
                stringRedisTemplate.opsForSet().remove(userFollowKey, followUserId.toString());
            }
        }
        return Result.ok();
    }

    @Override
    public Result isFollow(Long followUserId) {
        Long userId = UserHolder.getUser().getId();
        Integer followRecord = query()
                .eq("user_id", userId)
                .eq("follow_user_id", followUserId)
                .count();
        return Result.ok(followRecord > 0);
    }

    @Override
    public Result commonFollow(Long followUserId) {
        Long userId = UserHolder.getUser().getId();
        if (followUserId == null) {
            return Result.ok(Collections.emptyList());
        }
        String loginUserFollowkey = "follows:" + userId;
        String followUserFollowKey = "follows:" + followUserId;
        Set<String> intersect = stringRedisTemplate.opsForSet().intersect(loginUserFollowkey, followUserFollowKey);
        if (CollectionUtil.isEmpty(intersect)) {
            return Result.ok(Collections.emptyList());
        }
        //TODO 应该redis查不到 -> 数据库查 数据库查不到才是真的没有 这种处理暂时忽略

        List<Long> commonUsersId = intersect.stream().map(Long::valueOf).collect(Collectors.toList());
        List<User> users = userService.listByIds(commonUsersId);
        if(CollectionUtil.isEmpty(users)){
            return Result.fail("用户不存在");
        }
        // 转为DTO再返回
        List<UserDTO> userDTOList = users.stream().map(user -> {
            return BeanUtil.copyProperties(user, UserDTO.class);
        }).collect(Collectors.toList());

        return Result.ok(userDTOList);
    }
}
